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Aral Sea
The Aral Sea is a lake that lies between Kazakhstan and Uzbekistan. In 1960 it was the world's fourth largest lake, but by 1990, the lake had lost two-thirds of its former volume. Accompanying the decrease in volume, the shoreline retreated over 20 miles. The drastic shrinkage is the result of Soviet irrigation projects and has turned into what many consider to be "one of the planet's worst environmental disasters." With the change, the once flourishing fishing industry has become extinct. The change has also influenced the surrounding environment and people. Economic Impact The decrease in volume of the Aral Sea was also characterized by a sharp increase in the salinity of sea water. The salinity of water is determined by the mass of salts dissolved in the water and the volume of water. As the sea level dropped because of water loss, the inflow of salts to the Aral Sea exceeded the salt discharge, and as a result, salinity levels of the sea rose. In the first decade, the salinity increased by 14%, which exceeded the threshold for many commercial fish. As a result commercial fishing catches fell from 43,430 tons in 1960 to zero in 1980. Environmental Impact The decreasing volume of water in the Aral Sea's basin has resulted in the growing salinity of the remaining water. There huge deposits of salt along the shoreline as the water retreats have contributed to the growing temperature, loss of vegetation, and number of salt and dust storms in the region. There has also been a change in the Sea Surface Temperature. We see that the summer temperatures have been increasing, while winter temperatures have been decreasing. This is expected because as the sea looses volume, it's heat capacity is reduced, therefore it can warm up and cool off faster than before. The day to night variations in temperature, which are responsible for the sea breezes, have also increased. The changes have also characterized by less ice covering of the Aral Sea. This can be explained by the fact that increased salt concentration lowers the freezing point of water; therefore the temperature would now need to be lower for the water to turn into ice. The Aral Sea region experienced significant desertification during the recent decades. The desertification is characterized by degradation of the land and natural resources to the point that they can no longer be used. By cutting off water supply to a region, the hydrological balance of the area is lost. Frequent low-water periods contributed to the shortfall of needed resources for vegetation. The decline in the groundwater level contributed to the piling up of salt at the surface. A change in vegetative cover occured because the plants began to die away as a result of the increased salinity of the sea. Vegetation in the region was reduced by at least 40%. Six million hectares of agricultural land were destroyed as a result of salinization and desertification. The desiccation of the Aral Sea greatly increased the number of dust and salt storms in the area. Satellite images have revealed that there are up to ten major dust storms occurring annually in the region. While before, the pressure from the water surface dampened the strength of the northerly and north-easterly winds, the loss of the water meant that it's protective action from the wind was significantly reduced. The receding sea left behind large amount of salt, and groundwater evaporation further increased the amount of salt from the exposed sea bed. The strong north-easterly winds now pick up the sand, salt, and dust, creating strong dust storms. Health Impact The Aral Sea's dwindling ability to support the surrounding nations' water supplies has resulted in natives using irrigation cannels that are contaminated with chemical from fertilizers and pesticides as their water source. As of 1980, there has been a higher-than-expected recorded number of infections in the area for anemia and hepatitis B. The declining economy has resulted in poverty. As a result of that poverty, populations, birth and death rates increased dramatically. Life expectancy shrank due to worsening public health services. This region has the highest child mortality rate (75 children per 1000 newly born), and there is a high level of maternity deaths observed: about 120 women per 10,000 births. Due to increased dust storms, high concentrations of pesticides in the air, and poor quality of water, rates of diseases such as tuberculosis, infections and parasites, typhus, hepatitis and paratyphoid dramatically increased. In the recent decades, there has been a slowing of the growth of populations in the area. Diminishing resources have contributed to a growing number of people moving away from the region.